1. Field of the Invention
The present invention relates to a side surface light emitting type light emitting device mounted on the surface of a wiring board.
2. Description of the Related Art
An example of the light emitting device of the above-described type is disclosed in Patent Document 1. In this light emitting device, lead members are drawn out from both side parts of a reflecting case having a front part opened and a planar bottom part, and a terminal holding part is integrally provided in the rear part of the reflecting case. The parts of the lead members that are drawn out from the reflecting case are bent along the side surfaces of the terminal holding part from the side parts of the reflecting case, and further bent along the lower surface of the terminal holding part and ends thereof are accommodated in cut out parts as connecting parts.
On the other hand, Patent Document 2 discloses a side surface light emitting type light emitting device in which lead members are drawn out from the lower surface of a reflecting case of the light emitting device and bent along the lower surface of a terminal holding part. Further, Patent Document 3 discloses a structure that lead members drawn out from the lower part of a light reflecting case of a light emitting device and bent along the lower surface of a terminal holding part are further bent along the side surfaces of the terminal holding part.    Patent Document 1: JP-A-2006-253551    Patent Document 2: Japanese Design Registration No. 1171708    Patent Document 3: Japanese Design Registration No. 1288058
It has been required for a recent light emitting device to have a high output. Therefore, the light emitting device is liable to mount a high output LED chip thereon. The high output LED chip generates a great heat. When the temperature of the LED chip itself becomes high, the output of the LED chip is undesirably low. Thus, heat needs to be effectively radiated from the LED chip. Since a side surface light emitting type light emitting device is used as a light source of a display of a portable telephone, the side surface light emitting type light emitting device needs to be compact. Accordingly, a heat radiating member such as a heat sink is not used to transmit the heat to a wiring board through a lead member on which the LED chip is mounted and radiate the heat. In the light emitting device disclosed in the Patent Document 1, the lead members are drawn out from both the side parts of the reflecting case. However, since the side surface light emitting type light emitting device is long in a transverse direction, a heat radiating path is long so that a heat radiating effect is low. On the other hand, in the light emitting devices disclosed in the Patent Documents 2 and 3, since the lead members are drawn out from the lower surface of the reflecting case, a heat radiating path is short. However, since a drawn out part of the lead member is compact depending on the miniaturization of the light emitting device, a contact area of the lead members and the wiring board is relatively reduced. Thus, an adequate heat radiating effect cannot be obtained.